The present disclosure relates to concrete construction, and more particularly, but not exclusively, to a dowel bar assembly for connecting adjacent concrete slabs.
The construction of concrete surfaces is commonly accomplished by forming a plurality of adjacent concrete slabs that are separated by expansion joints. In some applications, the concrete slabs may support heavy loads, such as loads exerted by equipment on aircraft runways, taxiways, and parking aprons. The heavy loads that are supported by an individual concrete slab can cause vertical movement of the slab with respect to adjacent slabs. To prevent this damaging movement, the load may be distributed through load bearing dowels that extend between adjacent slabs across expansion joints. These dowels are typically formed from a ductile material, such as steel or fiberglass, which transmits the load and provides additional reinforcing structure. Different techniques exist for installing such dowel bars into a concrete slab.
One of the typical methods for installing dowel bars is to create a dowel bar assembly or apparatus that includes wire side rails for supporting a dowel bar in place prior to the pouring of a concrete slab. Typically, a dowel bar assembly is positioned in an area where two concrete slabs will abut one another. An expansion member may be mounted on the dowel bar assembly, and commonly delineates the respective edges of the concrete slabs. A first concrete slab is then poured along one side of the expansion member, partially covering the dowel bar assembly. A second concrete slab is subsequently poured along a second side of the expansion member, covering the other side of the dowel bar assembly. Therefore the two concrete slabs are separated by an expansion joint and connected together by the dowel bars to help distribute heavy loads across both of the concrete slabs.
Joining the wire side rails to the dowel bar is usually time consuming and costly. The wire rails are usually made of steel and susceptible to corrosion. Often, the corrosion spreads from the wire rails to the dowel bar. Previously, attempts to control the corrosion were made by coating the dowel bar with epoxy. However, commonly the side frame is welded to the epoxy coated dowel bar, and such welds enable corrosion to enter into the dowel bar even with the epoxy coating since the weld areas are not coated. Therefore, one drawback to this method of forming concrete slabs is increased corrosion. In addition, another drawback is the time consuming and costly method of constructing the dowel bar assembly. Furthermore, if the assembly is constructed at a factory, transport and storage of the devices becomes difficult and costly as well.
Therefore, many needs remain in this area of technology.